Expanding piston



July 27,1926. 1,594,286

E. H. WEBB ET AL EXPANDING PISTON Original Filed July 5, 9 5

Patented July 27, 1926.

UNITED STA ERNEST H. EBB AND WALTER K. 'sHInN, or MONTROSE,

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EXPANDING PISTON;

Application filed July 3, 1925, Serial This invention relates to trunk pistons for internal combustion engines, and particularly to expanding pistons.

The general object of our invention is to provide a piston, the skirt of which is constructed in two pieces, or in other words to provide a piston having a head and one section of the skirt and a second section of the skirt which is adapted to fit into place to complete the skirt of the piston, the two sections of the skirt being urged away from each other by internal rings.

A further object is to provide a piston so constructed that it will not wear or get loose in the cylinder and the expanding skirt will take up all of the wear and eliminate piston slap, thereby adding to the life of the motor or engine.

Other objects will appear in the course of the following description.

Our invention is illustrated in the accompanying drawing, wherein Figure 1 is an elevation of a piston constructed in accordance with our invention;

Figure 2 is a vertical sectional view thereof;

Figure 3 is a bottom plan View;

Figure 4 is an elevation of the piston at right angles to the point of view shown in Figure 1;

Figure 5 is a top plan view of one of the rings which expands the piston.

Referring to this drawing, 10 designates the head of the piston which has the usual circular shape and is grooved to receive the usual piston rings. The head has formed integrally therewith the downwardly extending skirt section 11 which is formed to provide the bearing 12 having the usual bushing 13. Opposite this bearing 12 the under face of the head 10 is formed with a downwardly extending web 14 constituting a wrist pin bearing in alignment with the bearing 12 and having the bushing 15.

The second section 16 of the skirt is arcuate in plan view and is formed to provide the inwardly extending bearing 17 having a bushing 18. The inner end of the bearing 17 will bear against the outer face of the web let and the wrist pin 19 will pass through the bearing 12, through the bushing 15, and through the bushing 18. The opposite faces of the skirt sections are formed with the flattened portions 20, as usual in pistons. The inner faces of the skirt sections 11 and 16 are formed with grooves 21 within which No. 41,387. Renewed March 16,1926.

are disposed the expansible rings One of these grooves is located just below the head of the piston and the other located ad jacent the lower end of the piston skirt as, for instance, just above the groove 23 for the skirt piston ring.

It will be seen that these parts may be readily assembled, that the two sections of the skirt are urged outward away from each other and against the walls of the cylinder, and that no slap can occur. This piston will not wear or get loose within the cylinder inasmuch as the expanding skirt will take up all wear and add very greatly to the life of the motor or engine. The web 14: fits against the re-entrant inner faces of the section 16 so that the section 16 cannot pivot upon the wrist pin 19 and furthermore this is prevented by the ring inserted in the groove 23.

e claim 1. An expansible piston of the character described comprising a head, circular in plan, and a skirt section, arcuate in plan, and the skirt section being formed to provide two oppositely disposed bearings, a second skirt section, arcuate in plan, and adapted to lit at its edges against the edges of the first named skirt section and against the outer face of one of said first named bearings and having a wrist pin bearing, a wrist pin passing through the three bearings, and means acting to yieldingly expand the two skirt sections.

2. A piston of the character described comprising a head and a skirt section, the head being circular in plan and the skirt section being arcuate in plan, the skirt, section being formed with a wrist pin bearing and the head having a downwardly extending arcuate web formed with a wrist pin bearing, a second skirt section complementary to the first section and fitting thereagainst and having a wrist pin bearing fitting against said web, a wrist pin passing through the three bearings, and upper and lower expansible rings disposed within the skirt sections and urging the skirt sections apart.

3. A piston of the character described comprising a circular head having piston ring grooves upon its periphery and formed with a skirt semi-circular in cross section, the skirt being formed with a piston ring groove and midway of the ends of the skirt with an inwardly extending wrist pin bearing, the head of the piston opposite said bearing having a downwardly extending web the two sections of the skirt being formed transverse to the axis of the wrist pin bearwith circular grooves at top and bottom of ing and formed with a wrist pin bearing, a the skirt, and resiliently expansible rings second skirt section semi-circular in plan disposed in said grooves and urging the two 5 and fitting against the first named skirt secsections of the skirt apart. 15 tion and having a wrist pin bearing midway In testimony whereof we hereunto afiix of its length and adapted to align with the our signatures. wrist pin bearing in the web,.bushings in the several bearings, a wrist pin extending ERNEST H. WEBB.

10 through said bushings, the inner faces of WALTER K. SHINN. 

